Mayo Clinic Minute: Men and testosterone

It's a hormone that makes men masculine. But it's often the one that causes the most confusion for men.

So much of a man's physical characteristics are affected by testosterone levels. And Dr. Landon Trost, a Mayo Clinic urologist, says a drop in testosterone level can cause a long list of side effects.

In this Mayo Clinic Minute, Dr. Trost explains what is considered a low testosterone value, how low testosterone can affect men's bodies, and why treating low testosterone does not always produce the results some men hope for. Ian Roth reports.

Journalists: Broadcast-quality video pkg (0:59) is in the downloads. Read the script.

Testosterone is the hormone most associated with masculinity.

"Everything from a deepening of voice, to muscles, to different characteristics on the jaw and so on, often are related to testosterone," says Dr. Trost.

He says, as men age, their testosterone levels tend to drop, causing a long list of possible symptoms, including decreased energy and sexual function, weight gain and muscle loss. But exactly what level is considered low testosterone, commonly referred to as "low T," depends on a lot of factors, including age. In general, Dr. Trost says a testosterone value of less than 300 nanograms per deciliter is considered below normal.

There are plenty of treatment options, from alternative agents to testosterone compounds, but all of them come with a risk of side effects, such as blood that is too thick. Dr. Trost says men who think they might have low testosterone should see their primary care provider to be tested, but it's important to remember there's only so much testosterone therapy can do.

"It won't improve all men," says Dr. Trost. "And it'll be a modest improvement in those that it does improve. So it's not a miracle cure or miracle drug."